HR: 15:20h
AN: B43C-07    [Abstracts]
TI: A scaling analysis of vegetation carbon uptake for the North American Carbon Program: What are we missing and what can we do about it?
AU: * Ollinger, S V
EM: scott.ollinger@unh.edu
AF: Complex Systems Research Center, University of New Hampshire, Durham, NH 03824 United States
AU: Smith, M
AF: USDA Forest Service, Northeastern Research Station, Durham, NH 03824 United States
AU: Jenkins, J P
EM: julian.jenkins@unh.edu
AF: Complex Systems Research Center, University of New Hampshire, Durham, NH 03824 United States
AU: Plourde, L C
EM: lucie.plourde@unh.edu
AF: Complex Systems Research Center, University of New Hampshire, Durham, NH 03824 United States
AU: Martin, M E
EM: mary.martin@unh.edu
AF: Complex Systems Research Center, University of New Hampshire, Durham, NH 03824 United States
AU: Hollinger, D Y
EM: dhollinger@fs.fed.us
AF: USDA Forest Service, Northeastern Research Station, Durham, NH 03824 United States
AU: Wofsy, S C
EM: scw@io.harvard.edu
AF: Atmospheric Sciences Department, Harvard University, Cambridge, MA 02138 United States
AU: Oren, R
EM: ramoren@duke.edu
AF: Duke University, Nicholas School of the Environment, Durham, NC 27708 United States
AU: Ellsworth, D S
EM: ellwor@umich.edu
AF: School of Natural Resources & Environment, University of Michigan, Ann Arbor, MI 48109 United States
AB: The ability to detect patterns of carbon assimilation by vegetation is a key component of the North American Carbon Program. To date, most efforts have focused on remote sensing of canopy leaf area index (LAI), which has been related to productivity across large resource gradients and can be estimated using spectral vegetation indices such as NDVI. However, a growing body of evidence suggests that approaches based solely on LAI may be problematic in dense plant canopies and in systems where variation in growth is driven to a greater extent by variation in physiological properties such as photosynthetic potential and light use efficiency. Because photosynthetic potential is strongly related to biochemical constituents such as nitrogen and chlorophyll concentrations in foliage, the ability to incorporate canopy chemistry into large-scale carbon cycling research would represent an important contribution to NACP research goals. Here, we present results from a study that examines the degree to which canopy nitrogen chemistry can serve as an integrator of C flux patterns over complex forested landscapes. The functional basis for using foliar N as a scalar of C uptake lies in the fact that the proteins responsible for CO2 capture by leaves (e.g. rubisco) account for the majority of nitrogen in plant canopies. This and other linkages between terrestrial C and N cycles has motivated several new advancements in the ability to detect canopy N using hyperspectral remote sensing. As part of an ongoing project, we have derived spatial coverages of canopy N at four eastern U.S. sites that are part of the AmeriFlux network and used these data to drive enhanced spatial estimates of gross carbon exchange. Results from these sites will be discussed along with plans for additional sites in other regions of North America.
DE: 1615 Biogeochemical processes (4805)
DE: 1640 Remote sensing
DE: 0315 Biosphere/atmosphere interactions
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting